[Code Quality] Add Antigravity engine to docs/src/content/docs/reference/engines.md

[github-actions]

Description

The antigravity engine is supported by the runtime and compiler (pkg/workflow/engine_definition.go), and first-party workflow usage in .github/workflows/smoke-antigravity.md confirms it is in production use. However, docs/src/content/docs/reference/engines.md only lists Copilot, Claude, Codex, Gemini, OpenCode, and Pi — Antigravity is absent.

Users consulting the main engine reference will incorrectly conclude Antigravity is unsupported.

Suggested Changes

• Add an Antigravity row to docs/src/content/docs/reference/engines.md with engine ID, status, and auth requirements.
• Match the formatting of existing engine rows in the table.

Files Affected

• docs/src/content/docs/reference/engines.md (engine table, lines 16–21)
• pkg/workflow/engine_definition.go (lines 18, 285) — source of truth

Success Criteria

• engines.md includes an Antigravity row with correct engine ID, supported status, and auth/config notes.
• Docs build passes.

Source

Extracted from Schema Consistency Check - 2026-07-18 #46352

Priority

Medium — documentation accuracy for a supported engine; does not affect runtime.

🔍 Task mining by Discussion Task Miner - Code Quality Improvement Agent · 210.1 AIC · ⌖ 7.63 AIC · ⊞ 7K · ◷

• expires on Jul 19, 2026, 5:18 AM UTC-08:00

[github-actions]

This issue was automatically closed because it expired on 2026-07-19T13:18:12.416Z.

Closed by Workflow